The invention generally relates to regulating coherent boundary reflections during generation of a modeled wavefield.
Seismic exploration involves surveying subterranean geological formations for hydrocarbon deposits. A survey typically involves deploying seismic source(s) and seismic sensors at predetermined locations. The sources generate seismic waves, which propagate into the geological formations creating pressure changes and vibrations along their way. Changes in elastic properties of the geological formation scatter the seismic waves, changing their direction of propagation and other properties. Part of the energy emitted by the sources reaches the seismic sensors. Some seismic sensors are sensitive to pressure changes (hydrophones), others to particle motion (e.g., geophones), and industrial surveys may deploy only one type of sensors or both. In response to the detected seismic events, the sensors generate electrical signals to produce seismic data. Analysis of the seismic data can then indicate the presence or absence of probable locations of hydrocarbon deposits.
Some surveys are known as “marine” surveys because they are conducted in marine environments. However, “marine” surveys may be conducted not only in saltwater environments, but also in fresh and brackish waters. In one type of marine survey, called a “towed-array” survey, an array of seismic sensor-containing streamers and sources is towed behind a survey vessel.
The measurements acquired in the seismic acquisition may be used to model wave propagation. The modeled wave propagation may be used in connection with full waveform inversion and/or reverse time migration to produce a velocity model of the subsurface.
The computational domain used in the modeling of the wavefield is finite, which introduces challenges in emulating a theoretically infinite wavefield. Therefore, there is a continuing need for better ways to model a wavefield using a finite computational domain.